Explosive composition having a liquid hydroxyalkyl nitrate as sensitizer

ABSTRACT

Hydroxyalkyl nitrates, particularly ethylene glycol mononitrate, propylene glycol mononitrate and hydroxychloropropyl nitrate are employed as part or whole replacements for nitroglycerine and/or ethyleneglycol dinitrate in substantially non-aqueous gelatins, semi-gelatins, dynamites and dry explosive compositions.

United States Patent 1 [111 3,881,970

Falconer et al. 1 May 6, 1975 EXPLOSIVE COMPOSITION HAVING A [58] Fieldof Search 149/88, 38, 47, 39, 60, LIQUID HYDROXYALKYL NITRATE AS 149/76,102-105 SENSITIZER [75] Inventors: Errol Linton Falconer, Mont [56]References Cited Saint-Hilaire, Quebec; Harold UNITED STATES T S WilliamHolden St, Hilaire 4 1972 4 4 Quebec, both of Canada 3 653 992 I Fee 19/ 7 X [73] Assignee: Canadian Industries Limited, PrimaryExaminer-Stephen J. Lechert, Jr.

Montreal, Quebec, Canada Attorney, Agent, or FirmDonald G. Ballantyne[22] Filed: Nov. 28, 1973 [2]] Appl. No.: 419,678 [57) ABSTRACTHydroxyalkyl nitrates, particularly ethylene glycol Relamd Apphcauo Dammononitrate, propylene glycol mononitrate and cominualion-ifl-parl 0f 1hydroxychloropropyl nitrate are employed as part or lg72- abandonedawhole replacements for nitroglycerine and/0r ethyl eneglycol dinitratein substantially non-aqueous gela- [52] US. Cl. 149/47; 149/76; 149/88;tins, sempgdatins, dynamites and dry explosive 149/92; 149/93; 149/102;149/103; 149/104; positions 7 Claims, No Drawings EXPLOSIVE COMPOSITIONHAVING A LIQUID HYDROXYALKYL NITRATE AS SENSITIZER This application is acontinuation-in-part of Ser. No. 305,337 filed Nov. 10, 1972, nowabandoned.

This invention relates to a sensitizing agent for substantiallywater-free explosive compositions and hence to such explosivecompositions deriving novelty through the presence therein of the saidsensitizing agent.

In the explosives art it has long been a desideratum to provide a safe,economic and practical substitute for nitroglycerine and ethylene glycoldinitrate sensitizers, generally referred to as NO and EGD respectively,in explosive compositions of the types generally known as gelatins,semi-gelatins and dynamites. Since NG and/or EGD are hazardous tomanufacture and to formulate into useable explosive mixtures and sincethe vapours of NG and/or EGD frequently produce undesirablephysiological effects on individuals exposed thereto, their use poses acontinuing problem in the explosive industry. It had been predicted thatthe non-toxic aqueous slurry explosives consisting of oxidizer salt/fuelmixtures in a gelled water matrix would eliminate most of theundesirable characteristics of NG/EGD-based explosives and eventuallydisplace many of them from the market. While to a substantial extentthis has happened, it has not been possible to match the sensitivity andpower of NG/EGD/based explosives, especially in small diameters withoutadding to the aqueous slurries costly sensitizing materials. The needcontinues, therefore, to employ NG/EGD as explosive sensitizers and thesearch for safer substitutes for these sensitizers has like-wisecontinued.

Ideally, an explosive sensitizer should possess the economy and strengthof conventional nitroglycerine/ ethylene glycol dinitrate without theexplosion and toxicity hazards associated therewith and at the same timethe sensitizer must be fully compatible with the mixture of ingredientsof an explosive compostion so as to produce the optimum in blastingperformance. Many sensitizers having a range of orders of sensitizationare known in the explosives art which have particular utility in varioustypes of explosives compositions. In addition to the liquid nitricesters like NG and EGD, these sensitizers include, for example, aromaticnitro compounds such as trinitrotoluene, nitroamine compounds such asnitroquanidine, powdered metals such as aluminium, nitrocellulosoe,smokeless powder, metalloids such silicon, and others Each sensitizerfinds specific utility in admixture with other compatible ingredients inparticular types of explosive compositions.

In the field of sensitized slurry explosives, for example Henry R. Feeand Elden K. Hurley, disclose in U.S. pat. No. 3,653,992 granted on Apr.4. l972, that a liquid nitrato-alkanol (hydroxyalkyl nitrate) may beemployed as the sensitizing constituent in pumpable or pourable aqueousslurry mixtures containing from 3 to 40% by weight of water. As noted byFee and Hurley, a liquid nitrato-alkanol is particularly suitable foruse as an aqueous slurry sensitizer since, in addition to being safe, itis freely soluble in the salt solution of a slurry, is compatible withthe thickened water used in the slurry matrix, is pumpable and requiresno separation from the salts and water which are introduced during itsmanufacture. However, even the improved nitrato-alkanol sensitizedslurry of Fee and Hurley has not matched, in terms of senstitivity anddensity, the NG/EGD sensitized type of explosives of the prior art.Indeed, the compositions of Fee and Hurley require the addition of gasbubbles in order to impart adequate sensitivity to these slurries. Suchbubble additives preclude the use of these slurries, at the presentstate of technology, in the types of packages customarily provided byNG/EGD sensitized explosives, namely, small diameter paper cartridgesused in underground mining.

It has now been surprisingly found that hydroxyalkyl nitrates,particularly exemplified by ethylene glycol mononitrate (EGMN), andpropylene glycol mononitrate (PGMN) and hydroxychloropropyl nitrate(HCPN), previously disclosed as useful only in aqueous slurryexplosives, are fully compatible with NG/EDG and may be successfullyemployed as part or whole replacements for NO and/or EGD insubstantially nonaqueous gelatinous, semi-gelatinous and dry explosivecompositions. By substantially non-aqueous is meant a compositioncontaining 3% or less by weight of water.

This invention therefore provides novel, substantially non-aqueousexplosive compositions containing as sensitizer constituents thereofhydroxyalkyl nitrates as substitutes for nitroglycerine and/or ethyleneglycol dinitrate.

A practical industrial method for the preparation of hydroxyalkylnitrate (HAN) consists in reacting an oxirane ring compound with anaqueous solution of ammonium nitrate and nitric acid. Ethylene oxide,for example, reacts to form ethylene glycol and EGMN in a dilutedsolution of nitric acid and ammonium nitrate. Other nitrate salts suchas sodium nitrate and calcium nitrate may be included in the reactivemixture. The end reaction product containing EGMN may be subjected to anextraction treatment for recovery of substantially pure EGMN.Alternatively, the end product may in most instances be used as such asa replacement or diluent for NO and/or EGD in conventional explosives ofthe gelatinous, semi-gelatinuous and dry dynamite types.

The invention is illustrated by the following Examples which are notmeant to be limitative as to the scope thereof. Percentages in allExamples are by weight.

EXAMPLE 1 Preparation of Ethylene Glycol Mononitrate (EGMN) One mole (44g.) of ethylene oxide was bubbled into a solution containing 200 g. ofammonium nitrate, 40 g. of sodium nitrate, g. of 98% nitric acid and g.of water and the mixture was cooled in an ice bath. The reaction wasexothermic and the temperature rose from 8to 20C. during the addition ofthe oxide. As soon as the addition of oxide ceased, the temperature fellrapidly and no ethylene oxide was evolved from the reaction vessel. Thisindicated a very rapid reaction. The EGMN formed did not separate fromthe aqueous solution, even when neutralized and saturated with ammoniumnitrate/sodium nitrate. The aqueous solution was extracted withmethylene chloride and a EGMN yield of 30-35% was obtained. This yieldwas very low and not representative of actual reaction yield but was theresult of simple partition of the product between two phases in which itwas completely miscible.

The EGMN isolated was shown by thin-layer chromatography and gas-liquidchromatography to consist mainly of EGMN with small quantities ofethylene glycol, ethylene glycol dinitrate and diethylene glycolmononitrate.

EXAMPLE 2 Another preparation of Ethylene Glycol Mononitrate (EGMN)Ethylene oxide was bubbled into a solution containing 500 g. of ammoniumnitrate, 80 g. of sodium nitrate. 160 g. of 98% nitric acid and 280 g.of water. The reaction temperature was maintained below 35C. by externalcooling. The oxide was metered into the solution at a rate of 1.2l./min. while 160 g. of 98% nitric acid was added dropwise over a periodof 57 minutes, the time required for the addition of 3 moles of oxide.An additional 6 moles of ethylene oxide and 320 g. of 98% nitric acidwere added in a similar manner, after which an extra 4 moles of theoxide were introduced into the system in order to neutralize the excessnitric acid. In a typical case, after a total of 13 moles of the oxidehad been absorbed, 2 ml. of 28% ammonium hydroxide solution (p 0.90)were required to bring the pH of the final solution to 7.0 Amaterial-balance calculation in the reaction products predictedapproximately the following composition:

Ammonium nitrate 24.1 Sodium nitrate 3.9 Water 1 1.5 Ethylene glycolmononitrate 51.4 Ethylene glycol 9.1

EXAMPLES 4 8 Preparation of EGMN In a pilot-plant batch reaction processas described in Example 2, the following EGMN liquors were produced. Thequantities shown are expressed as percent by weight.

Example 4 5 6 7 8 Ammonium nitrate 23.4 22.0 24.7 23.9 22.8 Sodiumnitrate 4.2 4.2 3.8 3.8 4.0 Water 12.8 15.7 11.9 11.5 15.3 EGMN 54.251.3 54.7 55.8 52.4 Ethylene glycol 5.4 6.8 4.8 5.0 5.5

Further additions of ethylene oxide and strong nitric acid can he madeto provide even higher concentrations (e g 7092) EGMN EXAMPLES 9 11Continuous preparation of EGMN A continuous process was employed toproduce EGMN liquors. Three vessels were connected in series andcomprised a mixing tank, a nitrator and a neutralizer. The vessels wereequipped with mixing devices, cooling devices and inlet and outletorifices. An acidic aqueous solution comprising from 26-33 parts byweight of ammonium nitrate, 46-52 parts by weight of strong 98% nitricacid and 15-25 parts by weight of water was prepared in the mixing tank.This solution was fed by pump into the nitrator where it was contactedwith ethylene oxide vapor. The feed rates of the solution and the vaporwere controlled so as to maintain a reaction temperature between about30C. and about C. which range reduced the production of side productssuch as ethylene glycol or ethylene glycol dinitrate. The desirednitration product on a weight percent basis is 1-12% nitric acid, 18-25%ammonium nitrate, 10-15% water, 2-8% ethylene glycol and 30-60% EGMN.The crude product from the nitrator overflowed continuously into theneutralizer where a gas sparger dispersed ammonia gas uniformly into thestirred reaction mixture. pH was controlled in the range 6.2 to 6.5. Inthis stage an additional 2-15% by weight of ammonium nitrate wasproduced from the reaction 0 of ammonia gas with residual nitric acidpresent. The

effluent from the outlet of the neutralizer was the desired finalproduct which normally contained from 40-60% by weight EGMN, 2-8% byweight of ethylene glycol, 2535% by weight of ammonium nitrate and10-25% by weight of water. The following EGMN liquors were produced bythe continuous process.

Example 9 10 ll Ammonium nitrate 27.5 29.2 25.9 Water 15.0 16.1 22.4EGMN 53.6 49.4 46.8 Ethylene glycol 3.8 5.3 4.9

EXAMPLE l2 Sensitivity of Ethylene Glycol Mononitrate (EGMN) EXAMPLES13-21 Preparation of PGMN and HCPN Batches of propylene glycolmononitrate and hydroxychloropropyl nitrate were made by a methodsimilar to that of Example 2. It was found, however, that high initialconcentrations of ammonium nitrate led to its crystallization as thereaction proceeded and that the presence of sodium nitrate caused aliquid-liquid phase separation during the reaction. Typically 50 g. ofammonium nitrate and 63 ml. of nitric acid served as a starting mixture.Propylene oxide or epichlorohydrin and 70% nitric acid were addedthrough separate inlets at the same molar ratio until 16-30 mol of acidhad been added followed by 5-17% excess of propylene oxide orepichlorohydrin. Additional ammonium nitrate can be added dissolved inthe nitric acid to maintain a high nitrate concentration. Up to 470 g.of ammonium nitrate remained in solution. Neutralization of the excessacid with liquid ammonia led, in the case of the propylene glycolmononitrate synthesis, to a liquidliquid phase separation with a moreconcentrated solution of the desired product, PGMN, In the upper layer.It was found with both syntheses that saturation of the system withsodium nitrateor calcium nitrate led to a more efficient separation inwhich the layer having the major portion of mononitrate ester containedcomparatively little water. This technique was therefore wellsuited tothe aims of the present invention. The preferred compositions of thefeeds to the reactor are compatible with the operation of the continuousprocess of Examples 9 l l Summarized are the analysis of representativebatch reaction products:

[Tutti] pic with a No. 6 electric blasting cap. This represents anexplosive with a controlled reduction in sensitivity when compared to anitroglycerine gelatine of equiva lent strength Notes txttmples i3. I4and were obtained by separation of the main liquor layer afterneutralization with ammonia [Example 16 was obtained from Example [5 bysaturation of the system with sodium nitrate and retention ofthesensitiierrich layer, Examples I9 and 20 were obtained as the one-phaseproduct of the reaction after neutralization with ammonia.

Example 2! was obtained from Example 20 by saturation 0| the system withsodium nitrate and retention ofthe SCHst- The preparation ofcompositions of hydroxyalkyl nitrate (HAN) which are analogous to theconventional high explosives based on nitroglycerine, ethylene glycoldinitrate or mixtures of these involves the isolation of substantiallyanhydrous HAN from aqueous liquors thereof. For illustrative purposes,this may be done by extraction of EGMN from reactor liquor withmethylcne chloride, which is then stripped off in an evaporator unit.

EXAMPLE 22 Gelatinized explosive composition EGMN/EU Nitrocellulose(dynamite grade) Ammonium nitrate tt lendcil fines) 55.5 Sodium nitrate(Chilean) l6 0 Vegetable meal 0.5 Wood pulp (l5 sulphur 0.4 Lalciurncarbonate (chalkl 0.4

A very extractable. full-bodied explosive composition was obtained whichdetonated (l X 8 inch cartridge) when initiated either with a primer of50% strength dyri unite or with high strength eiectric blasting cap at a\cioeity ol 2 57 km 'sec. The cartridge was not initiated While thetoxicological properties of ethylene glycol mononitrate are not fullyknown it is reported to be much less toxic than nitroglycerinc. lt has avapour pressure very similar to ethylene glycol dinitrate which is thevolatile and predominant constituent of all the nitroglycerines ofmodern commerce. Nevertheless, in both controlled exposures and inextensive work periods with EGMN, none of the characteristic NGheadaches caused by dinitrate vapours were experienced, Thus, anadditional property of explosives made with EGMN is the elimination ofthe headache-producing characteristics of NG-explosives.

Nitroglycerine was found to have remarkable and unexpected solubilitycharacteristics with respect to EGMN liquors When a nitroglycerine whichhas been made from a feedstock containing l5% glycerine and ethyleneglycol was mixed with the EGMN liquor of Example l3, no phase-separationoccurred at up to 12% NG, in spite of the fact that the system containedabout l4% water and 24% dissolved saits. At higher levels ofnitroglycerine, clean efficient separation into layers was obtained.with good extraction of EGMN Into the predominantly organic layervFurther dehydration of this layer could be accomplished by the additionof compounds immiscible with water Dinitrotoluene or moltentrinitrotoluene were found to be effective extractants for the hydroxyalkyl nitrate constituents from reactor liquors EXAMPLE 23 27Gelatinized explosive compositions Concentrated solutions of EGMN wereprepared by mixxing together reactor liquors with explosive ingredientswhich promote phase separation as described heretofore Gelatin-typecompositions were prepared from these solutions by techniques well knownin the art with the results summariz ed below, the proportions shownbeing in percent by weight Example 23 Z4 2o 27 by eight ol 4% 77 77 7]his EGMN liquor (lit. 5! (Ex, h) (Ex. ('1) tl-Ix. ht {Ex hr i by eight\Il 52 2. 23 I IS 5 explosne separation (85 (i-NO ($5 (LNG) (K5 (i-Nfii{H5 (i-NG) (H5 (LNG) promoter (hr/I (U; "1' h ucighl of organic phaseisolated 59.5 59.5 no.5 fall 7 lixplosne compositions Organic phase 31ill] 30.1? 251) Bill! 250 D3. minute nitrocotton 5.95 U 5 (1. l 5 0.5Ammonium nitrate fines 51.51) 55.8 4a.; 51o 51o Sodium nitrate ll) lltillM Zlll) IS U I) Wheat t'lour 1115 A 4 egetuhle meal 1 fill H) H) illto \NtmLl pulp lllll llfl 1).] U 7 ll? Sulphur IIHU (L5 05 [L4 0.7Calcium carbonate 0.5 (I5 (I 5 U4 (i 4 TNT lt'lakesl 4 5.0 A DetonationsPaper cartridge I'W'XX" l /4" 8" ll WXR" li WXH" ll H'Xti" Primer No 6EB cap No. 6 EB cap No. r1 EB cup No. l EB cap High strength capTemperature 40F. 40F. 40F -ltlli 4Ul- \'cl of det tkmi'sec l FIR 11h Z37 I (13 Ill Nilrit c lcr mixture ol cllitlene glycol and lii gi tcrineExample 23 had a mixed density of 1.47 g./cm and had a soft consistencywhich extruded easily and cleanly for cartridging. the composition wasstill soft were found to work more efficiently if a small amount ofhydroxyethylcellulose of high molecular weight was added and swelledfirst.

(Contains about 26% hydroxychloropropyl nitrate and about (Containsabout 25W propylene glycol mononitratc and about Detonation testsunconfined Polyethylene cartridge diameter Primer (pentolitc Results 2.water! i 1% water) 4 inches 4 inches bl] gr fill g. Detonuted DctonatedLiquor CltllCLnlhilCLl from intniple l? h mturution \\ith sodinm nitrateEXAMPLES 28 -29 Gelatin-type explosive compositions Gelatin-typeexplosives of a somewhat lower sensitiv ity were prepared from propyleneglycol mononitrate and hydroxychloropropyl nitrate liquors. The lowwaterconcentrate liquors swelled nitrocellulose. but

EXAMPLES 3O -33 Gelatinized explosive compositions Sensitizcr liquorswere prepared by admixture of the low-water liquors like Examples 16 and21 with standard EGMN liquors like Examples 9 l l and saturating amountsof salt. For example. parts of PGMN liquor and 200 parts of EGMN liquorwere mixxed with sodium nitrate; 209 parts of sensitizer-rich layer separated which contained only i 1% water and l5% ammo nium nitrate.

The low water-levels attained in liquor concentrates were advantageousof the preparation of gelatinized compositions containing nitroglycerin.without need for addtional liquid-phaseseparation operations of the typedescribed in Examples 23 27. These are illustrated in Examples 30 33with compositions given in percent by weight.

Semi-gelatin types Gelatin types Ex. 30 Ex. 3] Ex. 32 Ex. 33

Liquor l l0 l" l5 Nitroglyce rine l0 l0 l5 l5 Nitrocotton 0.5 0.5 0.80.8 Ammonium nitrate (blended fines) 75 9 75.9 53.9 66.4 Sodium nitrateI20 Vegetable pulps 2.5 2.5 2.5 2.0 Sulphur 0.3 0.3 0.3 0.3 Stearic acid0.5 (1.5 Chalk 0.3 0.3 0 5 0.5 Detonation tests (uneonfinedin 1%"diameter polyethylene cartridgcsl initiator cap No. 2 No. 4 No. 6 No. 4

Fill F/C EB F/C Velocity of detonation (km/sec.) 2.9 2.9 2.2 2.3

'EGMNJPGMN liquor concentrate described uhmc PGMN liquor. Example lo"PUMN liquor concentrated from Example l7 by saturation with sodiumnitrate HCPN liquor. Example Zl EXAMPLE 34 Substantially dry, dynamitetype explosive composition Low'nitroglycerinecontaining dynamitecompositions typically employ about 9% nitroglycerine. A typical EGMNliquor used at about a level in place of nitroglycerine and inconjunction with usual oxygen-supplying salts and dopes formulated indynamite would introduce 2 3% water and 8 ll% ethylene glycolmononitrate into the formulation. These water levels were deemed to beacceptable and no drying of an EGMN liquor was necessary before use insuch a composition. A composition was made up having the formula:

EGMN liquor (Example 9) l8.0% Ammonium nitrate (fine) 63.3 Sodiumnitrate (Chilean) 10.0 Vegetable meal 20 Wood pulp 2.0 Wheat flour 1.5Tamarind flour 3.0 Calcium carbonate 0 ,2

The composition was of a damp, cohesive consistency typical ofconventional dynamite and in a four inch diameter paper cartridgeunconfined, this formulation gave a strong detonation at 70F. wheninitiated with a high-strength cap EXAMPLE 35 Substantially dry,dynamite type explosive compositions An explosive composition containingrelatively large proportions of liquid hydroxyalkyl nitrate sensitizer,

thickened with nitrocellulose, and rendered rather dry in consistency byadmixture with cellulosic pulp, is exemplified in the following formula:

Hydroxyalkyl nitrate liquor (Example 2ll 45.0 Hydroxyethyl cellulose 02Nitrocotton 1.2 Sodium nitrate 4o.2 Ccllulosic pulps 7.0 Chalk 0,4Detonation tests (unconfinedl Polyethylene cartridge diameter 3" Primer(pentolite) (10 g. Velocity of detonation 2.4

(km/sec.)

EXAMPLES 36 43 Dry blasting agent compositions Dry blasting agentsnormally employed in dry boreholes especially in open-pit mining andquarrying operations, are exemplified by the ammonium nitrate-fuel oil(ANFO) compositions. ANFO has been shown to be both economic and safebut suffers somewhat from an intrinsic insensitivity which requiressubstantial priming of a charge for initiation and propagation. It hasnow been found that the addition of hydroxyalkyl nitrate (HAN) liquor totypical AN FO compositions enhances their sensitivity. Advantage canalso be taken of the solubility of nitroglycerine in HAN liquor to introduce small proportions of NG into dry blasting agents for themanufacture of compositions of exceptional sensitivity. Because the NGis soluble and dissolved, it can be uniformly distributed throughout thedry compositions in a highly dilute form.

Detonation tests on the dry blasting agent formulations shown below werecarried out by placing the explosive in a 4-inch diameter polyethylenebag on a steel plate supported on a lead bar of l X V4 inch crosssection bent into the form of a circle. A strong detonation severelyflattened this lead bar.

All the examples are demonstrably more sensitive than the control, astandard ammonium nitrate/fuel oil explosive prepared with the porousprills. Standard ANFO normally requires a No. 6 EB cap plus five No. 8blasting caps for a strong detonation. The proportions shown are in percent by weight.

- fontinued Example Control h r Nu h l li caps No K ltll caps What weclaim is:

l. A substantially non-aqueous explosive composi tion having a watercontent of less than 3% by weight and having as a sensitizer at leastone liquid hydroxyalkyl nitrate.

2. An explosive composition as claimed in claim 1 wherein the liquidhydroxyalkyl nitrate sensitizer is lected from ethylene glycolmononitratc, propylene glycol mononitrate. hydroxychloropropyl nitrateand mixtures thereof.

3. An explosive composition as claimed in claim 1 having an extrudablegelatinous consistency comprising essentially from 40 to 80% by weightof oxygensupplying salt. from I to 15% by weight of carbonaceousmaterial, at least 5% by weight of liquid hydroxxyalkyl nitratesensitizer and adjusted to a gelatinous consistency by the furtherincorporation of gelproducing liquid/thickener combination 4. Anexplosive composition as claimed in claim I having a tampable, cohesiveconsistency comprising can 1 il l l: l l H! l high strength clip 1 hlghstrength cu essentially from 5 to 40% by weight of liquid hydroxyalkylnitrate sensitizer, from 40 to by weight of0xygen-supplying salt from Ito l5% by Weight of carbonaceous material, up to 10% by weight of agelextending liquid and a thickening additive S. An explosivecomposition as claimed in claim 1 having a dry blasting agentconsistency comprising essentially from 65 to by weight of particulateammonium nitrate, from 0.5 to 15% by weight of carbonaceous material andfrom 2 to 20% by weight of liquid hydroxyall-tyl nitrate sensitizer.

6. An explosive composition as claimed in claim 1 also containing atleast one supplementary sensitizer material.

7. An explosive composition as claimed in claim 6 wherein thesupplementary sensitizer material is selected from particulate metal.ethylene glycol dinitrate nitroglycerine, pentaerythritol tetranitrte,dinitrotoluene. alkylamine nitrate, alkanolamine nitrate, ammoniumperchlorate and mixtures thereofv

1. A SUBSTANTIALLY NON-AQUEOUS EXPLOSIVE COMPOSITION HAVING A WATERCONTENT OF LESS THAN 3% BY WEIGHT AND HAVING AS A SENSITIZER AT LEASTONE LIQUID HYDROXYALKYL NITRATE.
 2. An explosive composition as claimedin claim 1 wherein the liquid hydroxyalkyl nitrate sensitizer isselected from ethylene glycol mononitrate, propylene glycol mononitrate,hydroxychloropropyl nitrate and mixtures thereof.
 3. An explosivecomposition as claimed in claim 1 having an extrudable gelatinousconsistency comprising essentially from 40 to 80% by weight ofoxygen-supplying salt, from 1 to 15% by weight of carbonaceous material,at least 5% by weight of liquid hydroxxyalkyl nitrate sensitizer andadjusted to a gelatinous consistency by the further incorporation ofgel-producing liquid/thickener combination.
 4. An explosive compositionas claimed in claim 1 having a tampable, cohesive consistency comprisingessentially from 5 to 40% by weight of liquid hydroxyalkyl nitratesensitizer, from 40 to 90% by weight of oxygen-supplying salt, from 1 to15% by weight of carbonaceous material, up to 10% by weight of agel-extending liquid and a thickening additive.
 5. An explosivecomposition as claimed in claim 1 having a Dry blasting agentconsistency comprising essentially from 65 to 95% by weight ofparticulate ammonium nitrate, from 0.5 to 15% by weight of carbonaceousmaterial and from 2 to 20% by weight of liquid hydroxyalkyl nitratesensitizer.
 6. An explosive composition as claimed in claim 1 alsocontaining at least one supplementary sensitizer material.
 7. Anexplosive composition as claimed in claim 6 wherein the supplementarysensitizer material is selected from particulate metal, ethylene glycoldinitrate, nitroglycerine, pentaerythritol tetranitrte, dinitrotoluene,alkylamine nitrate. alkanolamine nitrate, ammonium perchlorate andmixtures thereof.